Anyone disappointed with the FE movement?

Started Mar 11, 2014 | Discussions thread
Krich13 Contributing Member • Posts: 776
Re: Anyone disappointed with the FE movement?

Ramius wrote:

Very interesting to hear from you.

And what you say makes sense too, I just havent dared to ask the question but really, it should not be much more difficult to make an FE lenses than to make the elements bigger right? Bigger sensor needs bigger elements. When you already got a production set up lenses with all the tools in place, is it not actually quite easy to construct a new FE lens? Especially with all the computerwork involved in these things?

The optical design part is actually very easy: scaling things up linearly does most of the job. The subsequent optimization (even if needed at all) is not worth talking about.

Making the components work together is more difficult. Weight scales as cube of linear dimensions, so if you just enlarge every element of the Canon’s 22/2 1.6 times, the weight of each element would grow 4 times – and each would engulf 4 times as much special glass (if there is any) driving up the cost. Glass molding of larger elements is also not very easy (costs drop tremendously with lens sizes).

As a side note, dpreview posted the pics of lenses cut in half somewhere… The Zeiss Otus looks suspiciously like an enlarged double-Gauss followed by a speed booster. Hence the weight and the great MTF results (double-Gauss at relatively moderate aperture of say f/2 is no slouch on its own right, and the focal reducer boosts the performance still further). Likewise, The Sigma 18-35 also looks like a boosted FF design lens – and also has great MTF.

The lens still would be light enough for you to carry, and not that expensive to make. But the AF motor would still need to move 4 times the weight, making fast AF more challenging.

For Sigma 30 type lens, where only 20% scaling is needed, weight increase of 70% is far less critical. In principle, the aspheric element(s) could sit

On the other hand, FF lenses can have roughly 30% looser manufacturing tolerances which should partly offset the costs. Some aspherics could be made out of plastic instead of molded glass or as aspherized hybrids (spherical glass lens with a thin layer of plastic on top further driving down costs -- what wouldn’t be permissible for smaller sensor may become allowed on looser FF one).

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